1. Field of the Invention
The present invention relates generally to a recording condition compensation method, a program, a recording medium, and an information recording apparatus, and particularly to a recording condition compensation method for compensating a recording condition when recording information on an information recording medium, a program used in an information recording apparatus, a recording medium on which the program is recorded, and an information recording apparatus that records information on the information recording medium.
2. Description of the Related Art
In recent years and continuing, with the advancement of the performance of personal computers, there have been and are increasingly more personal computers that are capable of handling audio-visual (AV) information such as music and images. Since AV information generates a very large information storage requirement, optical disks such as compact disks (CD) and digital versatile disks (DVD) are attracting attention as information recording media. Thus, with the growing popularity of these optical disks, their prices are starting to drop, and also it is becoming increasingly common to include an optical disk apparatus as one of the peripherals of a personal computer, the optical disk apparatus functioning as an information recording apparatus of the personal computer. In the optical disk apparatus, the recording and erasing of information is realized by irradiating a microscopic laser beam spot on the recording side of the optical disk on which a spiral track or concentric tracks are formed, and replaying of information is realized via the reflection of light from the recording side. Also, in the optical disk apparatus, an optical pick-up device is implemented in order to irradiate the laser beam onto the recording side of the information recording medium and to receive the light reflected from the recording side.
Normally, the optical pick-up device includes a light source that emits a laser beam with predetermined light emission power (output), an optical system that guides the laser beam emitted from the light source onto the recording side of the information recording medium and guides the laser beam reflected from the recording side to a predetermined light receiving position, and a light receiving unit arranged at the light receiving position.
In the optical disk, information is recorded by arranging a mark area (pit) and a space area (land) to have predetermined lengths and to be in a predetermined combination. The mark area and the space area have differing reflection rates as is explained in detail below. In recording information on an optical disk, the light emission power of the light source is controlled so that a mark area and a space area are formed each with a predetermined length and at a predetermined position.
For example, in a recordable optical disk that includes organic dye in its recording layer (conveniently referred to as ‘dye disk’ hereinafter) such as a CD-R (CD-recordable), a DVD-R (DVD-recordable), or a DVD+R (DVD+recordable), the dye is heated and melted by increasing the light emission power so that a substrate portion that is in contact with the melted dye changes in quality and shape when forming the mark region. On the other hand, when forming the space area, the light emission power is controlled to be lower at about the same level as that used in a playback operation so that the substrate does not change in quality nor shape. Thus, the reflection rate is lower in the mark area compared to the space area.
Generally, in a dye disk, recording sensitivity is considerably susceptible to change in response to a change in the wavelength of the laser beam. Thus, when the wavelength of the laser beam changes, the optimum light emission power (also referred to as ‘recording power’ hereinafter) for forming the mark area changes as well. Also, in the optical pick-up device, when the temperature of the light source changes, the wavelength of the laser beam emitted from the light source changes as well. This in turn means that when the temperature of the light source changes, the optimum recording power changes as well.
Accordingly, in Japanese Patent Laid-Open Publication No. 2001-297437 (referred to as ‘publicly known art’ hereinafter), for example, an optical recording apparatus implementing a temperature sensor close to the optical pick-up device is disclosed. In this optical recording apparatus, the temperature around the optical pick-up device is detected with the temperature sensor upon recording, and if a change in temperature is detected to be above a predetermined value, the pulse form (also referred to as ‘recording strategy’ hereinafter) of the laser beam emitted from the light source may be changed, or a test writing for determining the optimum recording power (OPC: optimum power control) may be conducted.
Also, in a recordable optical disk, a test writing area for determining the optimum recording power for the optical disk is provided. This area is called a power calibration area (PCA). For example, a PCA in the CD-R has a test area that is divided into 100 partitions. Further, each partition of the test area is made up of 15 frames. Normally, in OPC (optimum power control), one partition is used to conduct a test writing of a predetermined set of data. Specifically, the test writing is performed by recording the predetermined data at a fixed linear speed while gradually changing the recording power in each frame. Then, the recording power with which the best recording quality is achieved is selected as the optimum recording power.
The relation between the temperature around the optical pick-up device and the optimum recording strategy cannot be determined unambiguously since this condition is greatly influenced by various factors such as the characteristics of the light source, the recording sensitivity of the information recording medium, and the recording speed. However, in the optical recording apparatus disclosed in the above-mentioned publicly known art, when a temperature change is determined to be above a predetermined value, only the temperature around the optical pick-up device is taken into account in changing the recording strategy. Thus, the selected recording strategy may not necessarily be the optimum recording strategy, and this may cause a degradation in the recording quality.
Also, in the optical recording apparatus disclosed in the above-mentioned publicly known art, OPC is performed each time the temperature change exceeds a predetermined value and thus, there may be a shortage of partitions in the test writing area.